Lubricant pump



F. C. WOELFER LUBRICANT PUMP April 28, 1953 lll/111111I//llll/ll/lllll,

Filed 001'.. 7, 1949 A Tv'o RNE YS NVENTOR. 0% ulm() du?, #0MM fm G.||III O 1 f aa w F 0 al//Zm Y B m i M 4 4/ Patented Apr. 28, 1953 TENTOFFICE LUBRICANT PUMP Frank C.v Wcelfer, Cincinnati,

Ohio, assigner .to

Balcrank, Inc., Cincinnati, Ohio, a` corporation 'of Ohio ApplicationOctober 7, 1949, Serial No. 120,195 15 Claims. (Cl. 10S-48) Thisinvention. relates to lubricant dispensing pumps which are mounteddirectly upon a lubricantl drum or container, the pump having anelongated cylinder submerged in the lubricant to deliver it underpressure from the drum to the point of use. Such pumps are applied topres- Sure lubrication generally, and are used most extensively inservice stations for chassis lubrication jobs,- the pump unit serving towithdraw the lubricant from its shipping drum for-discharge underpressure into one or more flexible delivery tubes. These tubes areequipped with control nozzles which can be coupled conveniently tothegrease fittings of automobiles, trucks or the like for pressureinjection of the lubricant directly into the fittings.

It is essential for ecient operation of a dispensing pump of this natureth-at the delivery chamber of the pump cylinder be lled completely withafresh charge of lubricant upon each Stroke of the pump piston,otherwise the pump operates at reduced capacity. In pumping ordinaryliquids, such as oils orlight greases, this is notg'a serious :problemsince 'such 4lubricants flow readily into the pump cylinder while backflow can -be controlled by a simple arrangement of check valves.However, in dispensing heavy oils andgreases having limited flowability,.it is difcultfto charge the-cylinder because vofflubricantsluggishness; furthermore, thepumpfcylinder is apt to become'air-boundafterea period-:of service, rendering the `pumppartially or wholly:inoperative until itis-serviced.

- The principal 'objects Vof thepresent .invention have been to overcome-these-iproblems by the provision Vof .an improved lpump structurezcombined with a 'piston-'SWS air motor ywhich I is a1'- rang'ed toforce a full charge of lubricant into the cylinder -upon each-stroke in4spite of lubricant llowresistance, and to provide.. aA combinationofcheck valves'and pistons which eliminate air which may be entrained inthelgrease .by delivering the air through the pump to the rdeliverynozzle in an automatic manner, thus preventing the'pumpy unit fromybecoming air bound. The structure thus provided performs its functionin a Indreeiicient and reliable manner than those used inthe past and'is of exceptionallysimple and inexpensive construction.

Brieythe improved pump unit consists ofY an airY motor of the' pistontype; operating in conjunction with `an elongated/pump` cylinderassembly which is larrangf-:d to Abe submerged in the lubricantcontained in a drum so as to Withdraw the""lubric'z'ant'fromv the drumbysuCtiOn, force it by positive displacement intothe lowerend of thecylinder, then to discharge the lubricant by positive displacement underhigh pressure from the upper end of the cylinder to the delivery line.In order to provide a full intake charge for each pump stroke, thecylinder is provided with a pair of pistons and cooperating valves, onevalve and piston for crowding a full charge of lubricant into thecylinder and the other for simultaneously delivering a charge under high'pressure through the cylinder to the delivery line. Both pistonsoperate in tandem, being secured upon a single piston rod whichis'connected to the air motor piston for unitaryy reciprocation of thepistons. The lower or charging piston reciprocates in a charging chamberwhich develops a vacuum or partial vacuum in the charging chamber toadmit lubricant into the chamber during the downward stroke of thepiston; while `at the same time, `a charge is forced by positivedisplacement into the cylinder above the delivery piston.A During theupward stroke, the fresh charge which was induced into the chargingchamber is now `forced under pressure into the cylinder, while at thesame time, the preceding charge which is now above the delivery piston,is forced at high pressure by the delivery piston through the cylinderinto the delivery line.

In order-to assure -afulllubricant charge for each delivery stroke ofthe high pressure delivery piston, the charging chamber is made largerin diameter than the cylinder bore of the delivery piston, whereby thelubricant charge which is forced from thecharging chamber on the upwardpiston stroke, is greater than the delivery cylinder bore is capable ofreceiving; consequently, the charge iscrowded into the cylinder underback pressure while the excess is by-passed under resistance. Thisinsures complete filling ofthe cylinder above the delivery piston andforcibly displaces, along with the lubricant, any air which may beentrained -or pocketed in the lubricant charge.

To promote further the efficiency and reliability of the apparatus, itis arranged toydeliver lubricant under pressure during both pistonstrokes, thereby increasing output` capacity and reducing pressuresurges yin the delivery lines'. The pump thus constitutes a doubleacting pump in the sensey that a major charge of lubricant is deliveredunder high pressure during the upward or delivery stroke of the pistonrod while ,a secondary or minor charge of grease is delivered on thereturn or downward stroke at substantially 3 the same pressure. Theminor discharge is brought about in a very simple manner by providingdifferential diameters on the piston rod, so that the piston rod itselfproduces a fractional displacementJ of lubricant from the cylinderduring its downward movement.

The air motor piston includes major and minor air pressure areas whichare correlated with the major and minor delivery areas of the pumpassembly to develop a pumping force consistent with the resistancedeveloped respectively during the upward and downward strokes of thepiston rod. The minor piston area is under constant air pressure toforce the piston rod downwardly after each upward stroke, servingcoincidentally as above noted, to deliver the minor grease charge. Theair motor is supplied constantly with compressed air and operates'whenthe delivery line is open and stalls when the line is blocked;therefore, the lubricant is held under constant pressure vin thedelivery line or lines.

It is desirable to have the air motor stall with its major piston areasubjected to air pressure so that lubricant is maintained in the linesunder pressure by the delivery piston for immediate delivery whenrequired and also to prevent leakage of air when the unit is notoperating. This has been accomplished by correlating the air motorpiston areas with respect to the grease displacement areasdifferentially so that the downward stroke presents less resistance thanthe upward stroke. This causes the pump piston to complete its downwardstroke and stall at the beginning of its upward stroke after thedischarge nozzle is blocked. The air motor is equipped with a reversingvalve which is actuated by movements of the piston to provide sustainedreciprocation. This valve is tripped to reverse piston movement atcompletion of the downward stroke and to seal itself against air leakagewhen it is positioned to drive the piston upwardly; consequently, airleakage is eliminated after the piston completes its down stroke andstarts upwardly.

Further objects and advantages of the invention are more clearlydisclosed in the specifcation in conjunction with the accompanyingdrawings.

In the drawings:

Figure 1 is a vertical sectional view illustrating generally the airmotor and pump assembly.

Figure 2 is an enlarged fragmentary view of the lower portion of thepump cylinder illustrating the operation of the pistons and valvesduring the downward stroke of the piston rod.

Figure 3 is a fragmentary view similar to Figure 2, showing theoperation of the parts during the upward or delivery stroke of thepiston rod.

Figure 4 is an enlarged sectional view taken from Figure 1 furtherdetailing the packing gland assembly at the outlet end of the pumpcylinder.

Figure 5 is a sectional view taken on line 5 5, Figure l, detailing theconstruction of the shuttle valve.

Figure 6 is a sectional view taken on line 6 6, Figure l, detailing theconstruction of the lubricant charging inlet means.

Described with particular reference to Figure 1, the pump unit consistsessentially of an air motor indicated generally at l having an airoperated piston il and reversing valve i2, with an elongated pumpcylinder i3 extending downwardly from the air motor. The lower end ofthe cylinder is provided with a lubricant charging piston i5 securedupon a piston rod i6, which extends through the cylinder with its upperend connected to the air motor piston I l for reciprocation. The airmotor embodies a casing generally indicated at Il which is machined toform a cylinder I8, and includes passageways which conduct compressedair from an intake passageway the cylinder under control ofthe'reversing valve l2. As shown, the air motor casing i1 is mountedupon a lid or cover plate 2l having a central opening 22 for the pumpcylinder i3, the plate 2l preferably constituting a cover or lid whichmay be installed directly upon the original grease container.

Air motor The pump is designed to lift and deliver the lubricant underhigh pressure during the upward or delivery stroke and also to deliver asmall amount of grease during the downward or charging stroke, as moreclearly disclosed hereinafter.

For this purpose, the air motor' piston is arranged to actuate thepiston rod under maximum effective pressure during the upward ordelivery stroke area to force the rod downwardly at less pressure byproviding a reduced piston area on the upper side of the piston which issupplied constantly with air pressure. In other words, while thecompressed air supplied to the cylinder through port 20 is in constantcommunication with the upper end of the cylinder to urge the pistondownwardly', nevertheless, the effective piston area at the lower end ofthe piston is a multiple of the reduced area so as to forcel the pistonupwardly to deliver lubricant at pres-` sure suiiiciently great fordirect application to the bearing iittings.

In FigureA 1, the lower or major piston area is designated at 23 and theminor area is designated at 24. As shown, the piston is approximately atits downward limit of travel, with the reversing valve about to betripped to reverse the piston travel. The reversing valve l2 is actuatedby a stem 25 which is slidably mounted in the motor casing il andconnected to the piston Il by an arm 2t slidably cooperating with thestem to elevate the stem toward the upper limit of piston travel and tolower the stem'during the iinal downward movement of the piston, asindicated by the arrows. As shown, the lower portion of stemestablishing a connection with a toggle lever 28 which is pivoted as at29 and spring loaded by the compression spring unit 30 disposed abovethe pivot point. The toggle lever is arranged to snap the toggle past adead center position to4 at the limits of pis-` ton travel. In theposition shown in Figure 1,`

actuate the valve plunger 3| the valve plunger is in its open positionto exhaust the air from the major piston area 23 byl way of passageway32 through the exhaust ports 33 of the valve. Compressed air isconducted tov the minor piston area 24 by way of the supply' port 20,vertical passageway 34 and lateral open.

ing 35 through the wall of the cylinder. The spring loaded toggle lever28 is shown near its dead center position so that the valve is abouttobe reversed by continued downward movement l.

of the piston. When the toggle 28 snaps over,

exhaust ports 33 will be blocked by the seat 36. of valve plunger 3l andthe tapered seat 31 will?, be opened to admit air from verticalpassageway"- 3d, lateral passageway 38, through the valve to` lateralpassageway 32 which communicates with" 25 embodies a necked. portion 21ythe .-majorfpiston-area 23 to causeupward travel of. .the Apiston landdeliveryof grease. .When the pump' is placed infoperation, com'- pressedair is supplied constantly to theair motor so thatthe lubricant supplylines are under pressure atalltimes with the airinotor stalledagainstback pressure unless the line or lines are opened toperrnit the passageof lubricantA and opera.- tion, of the motor. At this point, it is to benoted that by. reason of ,the constanty compressed air supplytothe minorpiston area 24, coupled with the fact thatthe piston rod.v movesdownwardly with. minimum resistance,.the air motor piston alwayscompletes its cycle of piston at its downward vlimit of if the lubricantdelivery "line is thapistonis moving in its itrwill follow through automtravel. Thus,

downward stroke, atically until the piston tripsl the valvevat.itsdownward stroke limit. In this position, air is admitted tothe majorpiston area and the piston is stalled by lubricant back pressures and isready to deliver lubricant immediately whenv the delivery line again isopened; also, seat 3S of the valve plunger 3l is closed to preventleakage of air while thel unit is stalled.

" Pump 'cylinder assembly vThe ,lubricantY cylinder consists of threesections; an upper section 39' which may be designated .as a deliverycylinder, an intermediate or displacementv cylinder .liiand a' lower orcharge ing .cylinder 1li', the' respective sections being screwedtogether asvat {l2-942.. The cylinder is provided 'with a, pair ofpistons, 'they charging 0'1" primary, piston l5 whichrecprocatesincylinderv 4l and a highv pressure ldi'splacenu-:nt or sec; ondary pistonl2` which' recprocatesin the'displacement cylinder 4G; and thepassage'of lubricant is regulated by a. shuttlevalve 58 anda balllcheckpvalve fil., The upper end ,of the de livery cylinder 39 isscrewthreaded las at 43 into a fitting M to which is connected valateral de: livery coupling l5 which preferably .includes 1a checkvalve. Fitting M formsa partici? alpacking gland indicated generally` atlit, and 1 is clamped Within a boss 47 Aforrned as' an integral part ofthe air motor casing, I '1. jA clamping nutriti" is screwthreade'd'asatjlil into thefboss, with Vits upper end engagedvagainstashoulder 5Dformed in't'ti'ng it. The lateral 'delre'ry tubeA i5 is screwthreadedinto the fitting @sat 5i and passes through anopening formed inbOss 4l."The delivery lines andl dispensingflllozzles do''not form a part ci? thepresent invention, and since they lire well known in the art/they areomitted from this disclosure. Thel delivery line, whichconsists'usu'allycf av iiexible hose capable o'ffwithstariding highpressure', may be connected directly to the delivery rality of flexibledelivery tubes maybe connected to a manifold pipe which is supplied'froinithe coupling to provide multiple outlets from a sin gle pumpunit.

`The upper. end of the piston rod l5 is connected to the air motorpiston il by a' coupling nut 52 threaded to the lower end of a thiinbleA53 formed as an integral part of the air motor piston. The coupling nutincludes an internal shoulder Eli and the rod iii includes a nut 55screwthreaded upon its end and conned between the shoulder 5d` andthethirnble ,53 to transmit the movements of the piston to the rod. Aslight radial clearance is maintained aroundjthe nut and piston rod topermit the -rod to align itself with respect to thepiston H topreventbindingof the V operation with the blocked ,whilel coupling 45;"01" aplu? 'upper endof the parts: *The i n xbriautv Ychargingy piston s 1151iis' clamped Vupon'the lower 'encbofthe pistonrod assembly between ea-4shoulderi and 'afnut' .5T screwthreaded up n a counter-turnedportion o1therod. f f f 'Thelower portion of charging` cylinder'dl is pr'lnridedwithy ports 6l whichy are traversed by piston l5 to'charge the cylinderby suction on the downward piston'strolsei `The vacuum or partialvacuumrorinducing the ow 'of lubricant into' the charging'cylinder landfor lpreventingbackoW'from-displacernent cylinder 4D is provided by -ashuttle valve l58-y which is slidably mounted uponthepistorr rodA is andarranged toseat against the upper end ofthe charging cylinder duringthedownward stroke ofthefpiston: rod." as shown in'Figure 2; y'Iheshuttle valve ESV-consiste essentially of asleeve and its upper end` isprovided with spaced ears 59 engageable against the shoulder- Gti-ofvcylinder 40 to limit upward movementof the valve and-to providevlubricantpassageways. The operationl of the charging pistonand shuttle`valve' `is described with greater detail in a'succeeding section ofAthis specification. ,v I f i f 7 hSurrounding theports 6l is acylindrical perv foratejacket'nor lfilter screen e2, consisting of anAupper ring 63 slidablyrtted upon cylinder 4l and a lower capscrewthreaded as at-upon the lower end of the cylinder. r A line meshcylindri a1 screen 6G is secured to the ring-63- and cap 64, spaced`frornthe cylinder and enclosing theports 6l to screen'fth'e lubricantwhichinay pass into the lower end of cylinderfill. v .Tlitjecfiliy 64and 'ring 63 are secured together byaplurality o f vertical rods til',having' ytheiry endsl anchored in thecap and' ring toA space them andserving also to reinforcethe screen'agamst collapse."

'From thedisplacement [cylinder 40 `the lubrcant passes' througha ballcheck Valve generally, indicated at 'H and is'dscliarged under highpressure' by" the vdisp'lace'ment piston indicated generallyatjlZ'reciprocating in the bore of cylind'erglli). '.*Described in detail,check valve 1Hand pist'v Jg'are interposed in thepiston-rod 'I6 by the'provision' of 'ant insert tube 73 having its oppositeends screwthreade'das at'i' and 75 upon the adjoining ends ci" the piston 'rod sections'.

uti-esiA and 3) encirclingfthe )tubey I3 and in Sliding Iengagainentrwiththe bore yor the displacematerial-having othe necessary resiliency?The the fheadel byflneans lof a spacer co1la`r'83`engaged byawasher811il which', in turn; is clamped against a shoulder of tube "73by the threaded serves also as Aa `"cage for 'thel placement chamber byway of the lateral ports 90 formed in the lower piston rod section. Theball check normally is maintained in its closed position by the spring9| which is maintained in compression between the ball and the end ofthe upper piston rod section. A spur S2 forming an extension of thepiston rod, passes downwardly through spring 9| to maintain the springin alignment with the ball. It will be observed in Figure 3, that theball check 89 seats against back flow during the upward stroke of thepiston rod for positive displacement of the lubricant under highpressure and unseats, las in Figure 2, during the downward stroke topermit lubricant trapped between the piston and shuttle Valve to passfrom the displacement cylinder to the delivery cylinder.

The packing gland assembly 46 at the top of the cylinder assemblyprovides a, double packing, one of which is effective to seal the pistonrod with respect to the air motor while the other prevents the escape oflubricant from the cylinder during delivery. The gland includes also awiper ring interposed between the two packings which is arranged to wipefrom the piston rod any lubricant which may adhere to it.

Described in detail with reference to Figure 4, the packing gland isenclosed by the boss 41 previously noted, and is clamped in position bythe clamping nut 48 which forces the packing gland assembly upwardlyagainst a shoulder 95 at the top of the boss. The air motor sealconsists of a closure plate 95 having an internal groove 9'! in which isconiined a resilient sealing ring B formed of synthetic rubber orplastic embracing the piston rod to establish a seal between the airmotor cylinder and rod. The plate 96 includes a shoulder |00, and asealing gasket |0| formed of a material similar to packing ring 98 ismaintained under compression between shoulders 9 5, and |00 to establisha seal.

The intermediate wiping ring |02 .is seated against the lower side ofclosure plate 96 and is tapered in cross section to provide a featheredwiping edge. The wiping ring |02 is conned in a cage |03 which includesan internal bore provided with holes |04 communicating with a lateralpassageway |05 to permit the lubricant to drain from the packingassembly through open-A ing v22 back to the drum. The ring |02 ismaintained in compression around the piston rod by a spring |06 mountedin compression within cage |03, having its upper end'seated against apressure ring |31. The pressure ring. |01 includes a cone shaped recessin its upper face which engages the feathered lower end of the wipingring to force the ring radially into a wiping engagement with the pistonrod. Cage |03 is clamped against the closure plate 96 by the fitting 44previously described.

vThe lower packing ring |08 which provides a lubricant seal around thepiston rod, is mounted within the bore ||0 formedin the upper end oftting 44. Ring |08 also is feathered in cross section and is maintainedin compression between the bore l0 and the piston rod by a shouldered'ring seated against the bottom of the bore, with its upper edge incompression against the packing ring. A washer |2 is placed abovepacking ring |08 in the bore and the assembly is maintained incompression by the clamping nut 48.

Operation In order to assure complete charging of the displacementcylinder 40 upon each stroke of the charging inder 4| is somewhatgreater in diameter than displacement cylinder 40. Otherwise expressed,the piston l5 tends to crowd a greater volume of lubricant into thedisplacement cylinder than it is capable of receiving, by reason of thedifferential in volumetric displacement between the two. Theoretically,this condition would impede operation of the charging piston I5 or jamit completely, since the lubricant is not compressible; however, apredetermined amount of clearance, indicated at S3, is provided betweenthe diameter of the charging piston l5 and its bore whereby the excessgrease is permitted to by-pass while under restricted ow and thusmaintain loading pressure upon the lubricant above the piston. By thisarrangement, complete charging of the displacement cylinder occurs oneach stroke and the output of the pump is kept at maximum.

Lubricant is displaced upwardly through the cylinder assembly in severalstages which can best be disclosed by identifying the successivechambers and the function of each. The cham- .ber of charging cylinder4| is indicated at A,

the chamber of displacement cylinder 40 is indicated at B and thepassageway of delivery cylinder 39 is indicated at C. During thedownward or charging stroke of the piston rod, as shown in Figure 2, avacuum or partial vacuum is developed in chamber A to load the chamberwhen the charging piston passes the ports 6| and, at the same time,lubricant which is trapped in chamber B between shuttle valve 58 anddelivery piston 72, passes through the ball check valve into thedelivery chamber C, as indicated by the arrows. Primarily, therefore,the downward piston stroke loads chamber A with a fresh charge oflubricant from the drum, and simultaneously transfers the charge inchamber B to chamber C. A given charge of lubricant thus passes throughthree stages of displacement successively through the chambers A, B andC' during one complete stroke cycle.

Upon execution of the upward or delivery stroke, as shown in Figure 3,the lubricant trapped in chamber A above charging piston i5 is forcedinto chamber B at a rate in excess of the displacement from chamber B toC by reason of the differential diameters of chambers A and B, as abovenoted. At the same time, the lubricant above the high pressure deliverypiston 12 is forced underhigh pressure through the delivery chamber C tothe outlet tube 45, the ball check valve 1| being, of course, closed toprevent back The cylinder assembly has been described up to this pointas single yacting in order to render more clearly its primary functions.However, in addition to recharging chamber A by vacuum and rechargingchamber C from chamber B during the downward piston stroke, the assemblyalso discharges a limited quantity of lubricant at full pressure throughoutlet tube 35 during the down stroke. The cylinder assembly thus may bedescribed as a modied double-acting unit. Otherwise expressed, the majorhigh pressure discharge of lubricant occurs during the discharge orupward stroke (Figure 3) and a minor discharge at substantially the samepressure occurs dur-ing the charging or downward stroke (Figure 2) sothat the discharge of lubricant occurs during both strokes of the cycle.

The minor or secondary discharge during the downward charging strokeoccurs by reason of piston |5, the bore of the charging cyla difference'in diameter between the upper and lower sections of the pistonrodassembly. As illustrated, the diameter of the" upper rod section,which is indicated at D, is greater than the diameter- 'E of the lowerrod section to cause displacement of lubricant equal to the differential:between rod sections D and E.' Thus, during the downwardstroke there isupward displacement of lubricant through the ball check valve -Tl and,at the saine time, rod section D ispassing into chamber C throughpacking gland' 46 and rod section E is passingou't of chamber B ythroughshuttle valve 58. Since the displacement of rod D which is enteringthecylinder isl greater vthan E, which leaving the'cylinder, aquantity'of lubricant equal to the diiferential is discharged from theoutlet tube liti.

inthe present disclosure, the differential between sections D and E issuiicient to maintain iull pressure at the deli\ ery nozzle with a.slight vdischarge of lubricant so4 as to eliminate substantially thesurges in pressure which otherwise would occur during the pumpingcycles.` "This has been found to improve efficiency since the volumedisplaced is increased and also because constant pressure isappliedtothe bearing being lubricated, thus giving the'lubricant an Opportunityto seep into the bearing during the return pump stroke. e

'As previously noted, the major area"23of the air motor piston il iseffective during the major deliverystroke of the high pressure deliverypistoni? and the ininor area is effective during the charging orret'urnstroke. The major air piston area 23 is a multiple of lubricant pistonarea 'l2 and the minor air piston' area 24 is a multiple of thedisplacementarea provided by the differential rod sections D and E.Under a given set of factors as to input air pressure; grease viscosityand temperature, the pump is capable of delivering lubricant atapproximately 6000 lbs. 1:-, s. i. at maximum volume on the upwarddelivery stroke and to discharge lubricant at substantially the sainepressure but at fractional volume during the return charging stroke.

The air rnoto'r is arranged to complete its downward stroke beforestopping by reason of the constant piston return air pressure suppliedto the minor piston area 2e, Ias noted previously. Since air pressure issupplied constantly to .air motor l and gre-ase delivery is controlledat `the nozzle by stalling the motor against. grease back pressure, thecharge of lubricant .in the pump must be discharged into the blockeddelivery line in order that the pump In'ay complete its downward stroke.It is found that the ilexible delivery hose will expand sufficiently toreceive the balance of the discharge since the discharge volume is veryslight in proportion to the hose area. `This permits the piston tocomplete its downward discharge stroke and .trip the valve toggle'leverto vdeliver compressed air to the major piston area which will cause thepiston Il to begin its upward stroke, then stall against lubricant backpressure.

In' order to cause the piston'to complete its downward stroke -in spiteof the minor grease delivery resistance, the diiferentialv piston rodsections Dand E are proportioned to require. less piston rod foice'thanthe delivery piston l2, bearing in mind that the volume discharged isa'small fraction of the major delivery volume; in other words, bycorrelating the major air piston area 23 to the delivery piston 'i2 toproduce agiven lubricant output pressure, `and-correlating the and.thisstreamy 10 minor piston area 2li with the diierentialroddisplacement areas D and E to produce slightly greater .output pressure,resistance on they down stroke is less than on the up stroke. Thisdiffer` ence-in resistance Ycauses piston Il to complete :its downstroke before stalling, the effect being to unbalancefpiston pressure inthedown direction.

It has-been found, by virtue ofv the arrangement of positivedisplacement chambers A, B and C,V incombination with the shuttle andcheck valves, that the improved pump assembly dischargesfthrough thecontrol lnozzle any aix` which may be trapped in the grease. This`eliminates the-need of manually bleeding air, which inthe past,frequently became trapped-in-grease pumps of this nature, rendering-thepumpj inoperative. tjis believed that air w'hichmay be drawnhintothefcharging cylinder fli'with, the lubricant,v is displaced readilyinto chamber B by reason of low resistance and ample Ipassagewaysthrough the shuttle valve 58. It is to be noted -atthis point that, byvirtue of the lslidable, engagement of the shuttle valve with the pistonrod, the valve is urged mechanically in itsopening and/closing movementsby the piston rod itself instead of by the fluid pressure passingthrough, it.v Inother words, since the valve is vnot springloaded, ilowresistance is reduced and the puinpoperates ymore efficiently.Afterpassinginto chamber B, the .air is forced lthrough ball check Ilbyupositive displacement since v,it is trapped between piston ,12 andshuttle valve'ell; It Iis Afound that ify the pump is lifted out ofthegrease drum while running, then Vplunged back linto the drum,y the -airthat has been sucked into thepurnp is forced out ahead of the greaseinstead of causingthel pumpf'to become air bound. A, v y f It is foundin practice, that the screen ,unit 62 surrounding the intake ports aids'in' charging lubricant into` the charging chamber, causing the chamberto force a lfull charge into the Vdis placement cylinderupon eachkupward strokaand causingthe-cylinder inturn, to deliver lubricant atvmaximum volume upon each upward stroke of thehigh pressure deliverypiston. The screen is of relatively fine mesh tohlter/out veryv linesolid particles-and naturally'resistspto alcertain extent, the freepassage of'viscous lubricant. lhev piston moves more rapidly `upon theydownward or charging stroke than upon the upward or deliverystroke,consequently giving the lubricant a'greater opportunity'. to flowinwardly through the lscreen thany outwardly. Moreover, during thedownward stroke of the charging piston, the piston has-a displacementeffect with respect to the. lubricantl within the `strainer jacket whichsurrounds the lower-portion of the cylinder. The impedance to the liowof 'lubricant through the meshes of the strainer, causes the strainer,in conjunction withthe cylinder which it surrounds,-to actas an annularytrap .withv respect to the lubricant. The downwardly moving vpistonthus provides a laterally flowingstreamof-lubricant ,under the localizedpressure of the .piston is; deflectedbythe jacket. up wardly-,aboutthepiston toward the open `portion of 'the intake ports; above thepiston. Thus, `the partialyacuuin y.drawn by theY piston islsatisedby-directing streams of additional lubricant towardy theports by thesustained displacement effect of the piston during the remainder ofthedownward stroke. Maintaining flowing. streams of lubricant internally`or the strainer jacket toward the intakegports forthe durationof thedownward stroke is of particular advantage with respect to stiiflubricants because it provides a time interval during which the slowmoving lubricant may ll in any void which may exist in the chargingchamber after the ports open. Tests have indicated that the output ofthe pump per stroke is measurably greater with the strainer installed onthe charging chamber as shown, due to the baflie action of the strainerwith respect to the lubricant, partially resisting the outward flow oflubricant under the displacement of the charging piston. i

Ordinarily, the pump unit will operate satisfactorily without a checkvalve in the delivery coupling 45 since the piston stalls in thedelivery stroke direction against back pressure. However, when severaldelivery lines are connected to a single pump, there is a tendency forthe delivery piston to be forced downwardly by back pressure in thelines after stalling and for this reason the unit performs moresatisfactorily with a check valve interposed in the line. As shown, thecoupling 45 consists of a cage H5 loosely conning a ball l I6 andprovided with cooperating seat I I1. The ball is maintained in the cageby a retainer IIB which is secured in position by a fitting H9screwthreaded into the cage. When excessive back pressure prevails, theball seats and prevents it from being imposed upon the pump piston.

Having described my invention, I claim:

1. A dispensing pump for viscous liquids comprising; a cylinder having acharging chamber at one end thereof and a delivery passageway at itsopposite end, a primary and secondary piston slidable in said chamberand cylinder respectively, valve means operable to charge the cylinderand chamber upon movement of the pistons in the charging direction andto advance both charges upon movement of the pistons in the deliverydirection whereby the charge in the charging chamber is forced underpressure into the cylinder and the charge in the cylinder is forcedunder greater pressure toward the said delivery passageway, and an airmotor having a piston connected to the primary and secondary pistons forreciprocating the same, the air motor piston having a major areaoperable to thrust the pistons under high pressure during the deliverystroke of the pistons and a minor area for thrusting the pistons at lowpressure during the charging stroke of the pistons, the minor pistonareav being under constant air pressure and the major area beingsupplied intermittently with air pressure to provide reciprocation.

2. A dispensing pump for viscous liquids comprising; a cylinder havingrespective charging and displacement chambers at one end thereof and adelivery 'passageway at its opposite end, respective pump pistonsslidable in said chambers, valve means operable to charge both of saidchambers with liquid upon movement of the pistons in one direction andto advance both charges under pressure upon movement of the pistons inthe opposite direction, the said charging chamber having a greaterdisplacement capacity than the displacement chamber to force the chargeunder pressure into the displacement chamber, and an air motor having apiston connected to the pump pistons for reciprocating the same, the airmotor piston having a major area under intermittent air pressureoperable to thrust the pump pistons at high pressure during theadvancing stroke and having a minor area under constant air pressureoperable to thrust the pistons at low pressure during the chargingstroke.

3. A lubricant dispensing pump comprising; an elongated cylinder havingrespective charging and displacement chambers at one end adapted to besubmerged in the lubricant and a delivery passageway at its oppositeend, respective pump pistons slidable in said charging and displacementchambers, valve means associated with the respective chambers operableto pass a charge of lubricant simultaneously from the charging chamberto the displacement chamber and from the displacement chamber toward thesaid delivery passageway during a delivery stroke of the said pistonsand to block the back flow of lubricant during a charging stroke of thepistons, the said charging chamber having an intake port arranged to betraversed by the piston to induce a charge of lubricant into the chamberby vacuum upon the charging stroke of the piston, and an air motorhaving a piston connected to the pump pistons, the motor piston having amajor area which is supplied intermittently with air pressure to thrustthe pistons in their delivery stroke and having a minor area which isunder constant air pressure to thrust the pistons in their chargingstroke and develop the vacuum in the charging chamber.

4. A lubricant dispensing pump comprising; an elcngated cylinder havingrespective charging and displacement chambers and a delivery passageway,respective pump pistons slidable in said respective charging anddisplacement chambers, valve means associated with the respectivechambers operable to pass a charge of lubricant simultaneously throughthe charging and displacement chambers during a delivery stroke of thepistons and to block back flow of lubricant during a charging stroke ofthe pistons, the said charging chamber having an intake port which istraversed by the charging piston and arranged to induce 9, charge oflubricant into the chamber under vacuum developed in the chamber duringthe charging stroke, and a fluid pressure motor having a pistonconnected to the said pump pistons for actuating the same, the motorpiston having a minor piston area which is under constant fluid pressureto drive the pump pistons in their charging stroke and having a majorpigtcn area under intermittent fluid pressure operable to drive the pumppistons in their displacement stroke against the constant force appliedby the minor piston area.

5. A lubricant pump comprising; an elongated cylinder having respectivecharging and displacement chambers at one end thereof and a deliverypassageway at its opposite end, respective charging and delivery pistonsslidable in said charging and displacement chambers, a piston rodconnected to said pistons and extending through the cylinder forreciprocating the pistons in unison in charging and delivering strokes,power means for reciprocating the piston rod, a valve seat interposedbetween the charging and displacement chambers, a movable check valvesleeve cooperating with said seat and slidably engaged upon the pistonrod, the check valve sleeve being adapted to engage said seat andthereby block lubricant back flow during the -charging stroke of thepistons and to develop a vacuum in the charging chamber during thecharging stroke, the chamber having an intake port which is traversed bythe charging piston to admit lubricant when the port is uncovered by the`charging piston, a second check .valve aswell operable to passlubricant from the displacement "chamber- 'to .theopposite side of the'delivery piston during the charging stroke and "to blocklubricant'baoknow during the delivery stroke, .the said piston rodhaving a'major diameter slidably sealed'with respect to theendof -thecylinder. and' al minor diameter slidably sealed with respect to .themovable check valvezsleeve and adapted to displace a minoricharge oflubricant fromthe cylinder duringtheeharging stroke of the piston rod,whereby lubricantis discharged through. the. delivery' passageway bothduring the .charging and delivery strokes.

f6.; A .lubricant pump comprising; an Velongated cylinder. havinglrespective @charging 'anddisplacement chambers .at one end thereof anda .delivery passageway at its oppositev end, a respectivecharging anddelivery piston 'slidablef in Isaid charging and displacement chambers,as piston rod" .connected to said pistonsfand 'extending .through-thecylinder. for reciprocating the pistonsincharging and delivery strokes,a sealrfor saidrod at the end of the cylinder opposite to the chargingand. displacement chambers, a'valve seat'fnterposed. between the.charging and displacement chambers, a. movable valveelement cooperatingwith said seat and slidablyl engaged uponthex piston rod, vthe movableVvalve"element bengadapted to block the iiowof lubricant dur the'charging stroke .of theipistonsythe said pistonrod -having diderentialdiameters: passing .through said seal and valve element adapted toprovide a. minor displacement v.oi lubricant during the` chargingstrokeof the rod and a major displacement during the delivery'v stroke,and an air. motor having a piston connectedto the said piston rod foractuating the samathe air' mo- .torvv piston having diierential areasfor reciprocating the piston rod atfhigh pressure during the deliverystroke of. the piston. rod and' vat low pres surenduring the chargingstrokezlof.A 'the piston md. Y 7.. A lubricant pump comprising; anelongated cylinder having respective. charging and` dis placementchambers at onefend thereof' and a delivery passageway' at itsv oppositeend, respec tives charging. and' delivery pistons slidabief in saidcharging` and displacement chambers; .a piston rod .connected to. saidpistons and Yextending .through the. cylinder for reciprocating the'pis-.tons inunisonpower meansior vreciprocating the piston rod in chargingand deliveryl strokes,` the said power means .being adapted toreciprocate the piston rod; at. a rapid rate 'during the chargin'gstrokeand at. a slow rate'v during the delivery- ,strokaavalve seat interposedbetween the charg-f ing; and displacement chambers, a movable valveelement ccoperating..withy said seat and. slidably engagedupon thepiston rod to block. lubricant backlovv from the displacement chamber tothe charging chamber during the charging strokel ofi thepistons and todevelop a vacuum in the charging; chamber during the charging stroke,thechargingV chamber having intake ports which are traversed bythe.charging piston, val-vev means operable to. pass. lubricant from the'displacement chamber during the. charging. stroke, 'and a screen,disposed in. spaced.. relationship upon the charging chamber surroundingthe intakefpmxtsV lto lter solid particles from the lubricant and. toprovide resistance to theflovv of lubricant Wherebylubricant. pressureis developed. with-in. the. screen by displacement of the chargingpiston at said rapid rate during the charging stroke'to supplementthe:charging of.. lubricant-(through rminor area is eiective the intakeports under K'vacuum Ywhen. the-ports are`uncovered-- f' '.8'. Inalubricant dispensing pump, having a delivery passageway, ber :at oneendrof the cylinder having an intake port, primary and secondary pumppistons-ldisposed Tin the charging chamber and cylinder respectively',respective valves for developing 'negative pressurein the chargingchamber forcharg ingthe same and. -for displacing lubricant through thecylinder during the strokes ofv the pistonsfan air motor forreciprocating the .pump pistons consisting A`of 4a cylinder having'anrair piston connected `to thepump' pistons, thecair piston having-amajor areaion one sidetandra minorareafon its .opposite side, means foradmitting' air pressure to the major pistoniareain termittently and.`for maintaining-constantfair pressure upon thel 'minor area to causereciprocation of the air and pump pistons whereby.v :the for developingthe i said negative* pressure in the charging chamber and thef-majorarea is Veiiectivez for delivering the lubricant .at high pressurefromtthelpump cylinder. f- .y 9. In a lubricant pump, a cylinderhaving-lubricant intake and 'delivery passageways,.ipistcn andval'vemeans for displacing 'lubricant under pressure through the cylinder, apistons'rodfcon.- nected tothe.` piston means havingdifferentialdiameters passing Ithrough the oppositelendsl-:of the cylinder andarranged vto .provide a :minor displacement of lubricant fromthecylinder'during the charging stroke of the piston. anair motor forreciprocating the pump piston-consisting of a cylinder having an'K airpiston connected to the said piston rod, the air. piston having a Aanda. minor areaonI `its a cylinder a `charging chammaintaining airpressure constantly upon.the minor area to. cause reciprocation of thevpiston', the said major area being eilcectivetodrivel'th'e pump pistonits discharge vstroke todeliver a major lubricant charge at a givenpressure fand the minor area being correlated to the differential pistonrod displacement` diameters to `dis placca minor lubricantcharge duringthe1charging stroke for delivery at .greater pressurefthan thenl'ajcuf'd-ischargf-.

'Yf-i l i 10'. In a; lubricant: dispensing pump, a oylinderhalvinglubricant .intake and. delivery'. paslmotor motor being. suppliedconstantly withcompressed air land arranged. to deliver lubricantautomatically and to stall at predetermined --lubricant' backA.p1-essure and 'having' a piston connected to the said piston rod, theair motor piston havingV afmaj'or and. minor area. arranged to provide adinerenmov-ement in the charging stroke than in the discharge strokecausing the -ai-r motorv piston to complete its charging stroke andactuate the said air valve means to supply air pressure to the majorpiston area prior to stalling under .lubricant back pressure. Y

11. In a lubricant pump, a cylinder having intake and deliverypassageways and piston and valve means for discharging lubricant, an airmotor for driving the pump having a motor` cylinder,. a piston slidablewithin the cylinder and having a major and minor area at opposite sidesthereof, means for maintaining constant air pressure against the minorpiston area, piston actuated valve means for admitting air pressure tothe major piston area and exhausting the same intermittently in responseto piston movements to reciprocate the piston against the constantpressure exerted by the minor area, a pump piston rod connected to theai-r motor piston, a major delivery,v pump piston secured upon the saidpiston rod related to the major area of the motor piston, the piston rodhaving differential lubricant displacement diameters related to theminor area of the motor piston, the said major area being soproportioned to the minor area to develop a differential thrustsufficient to displace the air maintained against the minor areaconcurrently with the pressure delivery of the major lubricant charge bythe pump piston, the i' piston rod being reciprocated in one directionby the said minor piston area to deliver a minor lubricant charge bypiston rod displacement at a given pressure and being reciprocated inthe opposite direction to deliver a major lubricant charge by pumppiston displacement at substantially the same pressure by air pressureeifective against the major piston area.

12. A lubricant pump suitable to transfer lu bricant from a lubricantsupply to the intake end of a high pressure grease dispensing pump, saidlubricant pump comprising a cylinder adapted to be mounted upon theintake end of the grease dispensing pump in a vertical positionsubmerged in the lubricant supply, a nonsealing piston in the cylinder,a piston rod extended upwa-rdly from the piston, a cylinder head on thelower end of the cylinder, the cylinder having intake ports in its lowerside wall extending upwardly above the cylinder head part way to the topof the cylinder, whereby the piston when on the level of the top of theintake ports subdivides the cylinder into an upper and a lowercompartment the volumes of which are unequal, the

volume of the lower compartment being. greater than that of the upper, acheck valve in the upper end of the cylinder providing one-way passageof lubricant upwardly from the cylinder into the intake end `of thegrease dispensing pump during the upward stroke of the piston, meansconnected to the upper end of said piston rod for reciprocating thepiston over substantially the full extent of the cylinder whereby thedownward stroke of the piston tends to create a void above the pistonand a localized positive lubricant pressure below the piston, and apervious jacket surrounding the ports in outwardly spaced relation tothe piston with its upper and lower ends joined to the cylinder aboveand below the intake ports, the jacket providing an annular trap aboutthe cylinder which is effective to impede the lateral ilcw of lubricantproduced by the downward stroke of the piston, whereby a localized flowof lubricant passes upwardly about the piston to equalize the lesserpressure above it.

13. A lubricant pump suitable to transfer'lubricant from a lubricantsupply to the intake end of a high pressure grease dispensing pump, saidlubricant pump comprising a cylinder adapted to be mounted upon theintake end of the grease dispensing pump in a vertical positionsubmerged in the lubricant supply, a non-sealing piston in the cylinder,a piston rod extended upwardly from the piston, a cylinder head on thelower end of the cylinder, the cylinder having an intake port in itslower side wall extending upwardly above the cylinder head part way tothe top of the cylinder, whereby the piston when on the level of the topof the intake port subdivides the cylinder into an upper and a lowercompartment the volumes of which are unequal, the Volume of the lowercompartment being greater than that of the upper, a check valve in theupper end of the cylinder providing one-way passage of lubricantupwardly from the cylinder into the intake end of the grease dispensingpump during the upward stroke o the piston, means connected to the upperend of said piston rod for reciprocating the piston over substantiallythe full extent of the cylinder whereby the downward stroke of thepiston tends to create a void above the piston and a localized positivelubricant pressure below the piston, and a pervious jacket surroundingthe port in outwardly spaced relation to the piston, the pervious jacketproviding a trap eiective to impede the lateral now of lubricantproduced by the downward stroke of the piston whereby a localized flowor lubricant passes upwardly about the piston to equalize the lesserpressure above it.

14. A lubricant pump suitable to transfer lubricant from a lubricantsupply to the intake end of a high pressure grease dispensing pump, saidlubricant pump comprising a cylinder adapted to be mounted upon theintake end of the grease dispensing pump in a Vertical positionsubmerged in the lubricant supply, a piston in the cylinder, a pistonrod extended upwardly from the piston, a cylinder head on the lower endof the cylinder, the cylinder having intake ports in its lower side wallextending upwardly above the cylinder head part way to the top of thecylinder, whereby the piston when on the level of the top of the intakeport subdivides the cylinder into an upper and lower compartment, thevolumes of which are unequal, the volume of the lower compartment beinggreater than the volume of the upper, a check valve in the upper end ofthe cylinder providing one-way passage of lubricant upwardly from thecylinder into the intake end of the grease dispensing pump during theupward stroke of the piston, means connected to the upper end of said.piston rod for reciprocating the piston over substantially the fullextent of the cylinder whereby the downward stroke of the piston tendsto create a void above the piston and a localized positive lubricantpressure below the piston, and a pervious jacket surrounding the portsin outwardly spaced relation to the piston with its upper and lower`ends joined to the cylinder above and below the intake ports, the jacketproviding an annular trap about the cylinder which is effective toimpede the lateral ow of lubricant produced by the downward stroke ofthe piston whereby a localized flow of lubricant passes upwardly aboutthe piston to equalize the lesser pressure above it, the piston duringupward movement being eiective to trap lubricant in the portion of thecylinder above the intake ports for transfer upwardly through the checkvalve to the grease dispensing pump, the piston having clearance withrespect to its cylinder to provide restricted downward passage oflubricant in excess of the intake capacity of the grease dispensingpump.

15. A lubricant pump adapted to extend Vertically into a lubricantcontainer to dispense lubricant under high pressure from the container,said lubricant pump comprising an elongated delivery cylinder having alubricant outlet at its upper end, a delivery piston, an upper pistonrod connected to the piston and passing siidably in sealed engagementthrough the upper end of the cylinder, a motor connected to the upperend of the piston rod for reciprocating the piston rod and piston, anintake check valve sleeve providing one-way passage of lubricantupwardly into the lower end of the cylinder during upward movement ofthe piston, a check valve associated with the piston providing passageof lubricant upwardly through the piston during downward movementthereof, a charging cylinder mounted upon the lower end of the deliverycylinder, a charging piston in the charging cylinder, a second pistonrod extending from the delivery piston downwardly to the charging pistonadapted to reciprocate the charging piston in unison with the deliverypiston, the second piston rod passing in sealed slidable engagementthrough the intake sleeve valve and having a diameter which is smallerthan the upper piston rod, the upper and v18 lower piston rods by theirsealed engagement at the upper and lower ends of the delivery cylinderand their dierential diameters being adapted to displace lubricant fromthe cylinder during the downward stroke, the charging cylinder havingelongated intake ports in its lower extent, the charging piston adaptedto draw a partial vacuum in the charging cylinder during the initialportion of the downward stroke and to traverse the intake ports duringthe remainder of the downward stroke, and a pervious jacket surroundingthe cylinder at said intake ports, the jacket providing an annular trapabout the cylinder effective to impede the flow of lubricant outwardlywhereby a iiowing stream of lubricant is deflected by the jacketupwardly about the piston to satisfy the partial vacuum above it duringsaid downward piston stroke.

FRANK C. WOELFER.

References iited in the file of this patent UNITED STATES PATENTS NumberName Date 2,922,232 Davis Nov. 26, 1935 2,357,029 Smith Aug. 29, 19442,357,030 Smith Aug. 29, 1944 2,399,172 Davis Apr. 30, 1946 2.409,962Shearman Oct. 22, 1946

